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1 – 10 of 80Qingfeng Xu, Hèrm Hofmeyer and Johan Maljaars
Simulations exist for the prediction of the behaviour of building structural systems under fire, including two-way coupled fire-structure interaction. However, these simulations…
Abstract
Purpose
Simulations exist for the prediction of the behaviour of building structural systems under fire, including two-way coupled fire-structure interaction. However, these simulations do not include detailed models of the connections, whereas these connections may impact the overall behaviour of the structure. Therefore, this paper proposes a two-scale method to include screw connections.
Design/methodology/approach
The two-scale method consists of (a) a global-scale model that models the overall structural system and (b) a small-scale model to describe a screw connection. Components in the global-scale model are connected by a spring element instead of a modelled screw, and the stiffness of this spring element is predicted by the small-scale model, updated at each load step. For computational efficiency, the small-scale model uses a proprietary technique to model the behaviour of the threads, verified by simulations that model the complete thread geometry, and validated by existing pull-out experiments. For four screw failure modes, load-deformation behaviour and failure predictions of the two-scale method are verified by a detailed system model. Additionally, the two-scale method is validated for a combined load case by existing experiments, and demonstrated for different temperatures. Finally, the two-scale method is illustrated as part of a two-way coupled fire-structure simulation.
Findings
It was shown that proprietary ”threaded connection interaction” can predict thread relevant failure modes, i.e. thread failure, shank tension failure, and pull-out. For bearing, shear, tension, and pull-out failure, load-deformation behaviour and failure predictions of the two-scale method correspond with the detailed system model and Eurocode predictions. Related to combined load cases, for a variety of experiments a good correlation has been found between experimental and simulation results, however, pull-out simulations were shown to be inconsistent.
Research limitations/implications
More research is needed before the two-scale method can be used under all conditions. This relates to the failure criteria for pull-out, combined load cases, and temperature loads.
Originality/value
The two-scale method bridges the existing very detailed small-scale screw models with present global-scale structural models, that in the best case only use springs. It shows to be insightful, for it contains a functional separation of scales, revealing their relationships, and it is computationally efficient as it allows for distributed computing. Furthermore, local small-scale non-convergence (e.g. a screw failing) can be handled without convergence problems in the global-scale structural model.
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Milad Shabanian and Nicole Leo Braxtan
3-ply cross-laminated timber (CLT) is used to investigate the thermo-mechanical performance of intermediate-size assemblies comprised of T-shaped welded slotted-in steel doweled…
Abstract
Purpose
3-ply cross-laminated timber (CLT) is used to investigate the thermo-mechanical performance of intermediate-size assemblies comprised of T-shaped welded slotted-in steel doweled connections and CLT beams at ambient temperature (AT), after and during non-standard fire exposure.
Design/methodology/approach
The first set of experiments was performed as a benchmark to find the load-carrying capacity of the assembly and investigate the failure modes at AT. The post-fire performance (PFP) test was performed to investigate the residual strength of the assembly after 30-min exposure to a non-standard fire. The fire-performance (FP) test was conducted to investigate the thermo-mechanical behavior of the loaded assembly during non-standard fire exposure. In this case, the assembly was loaded to 67% of AT load-carrying capacity and partially exposed to a non-standard fire for 75 min.
Findings
Embedment failure and plastic deformation of the dowels in the beam were the dominant failure modes at AT. The load-carrying capacity of the assembly was reduced to 45% of the ambient capacity after 30 min of fire exposure. Plastic bending of the dowels was the principal failure mode, with row shear in the mid-layer of the CLT beam and tear-out failure of the header sides also observed. During the FP test, ductile embedment failure of the timber in contact with the dowels was the major failure mode at elevated temperature.
Originality/value
This paper presents for the first time the thermo-mechanical performance of CLT beam-to-girder connections at three different thermal conditions. For this purpose, the outside layers of the CLT beams were aligned horizontally.
Highlights
Load-carrying capacity and failure modes of CLT beam-to-girder assembly with T-shaped steel doweled connections at ambient temperature presented.
Residual strength and failure modes of the assembly after 30-min partially exposure to the non-standard fire provided throughout the post-fire performance test.
Fire resistance of the assembly partially exposed to the non-standard fire highlighted.
Load-carrying capacity and failure modes of CLT beam-to-girder assembly with T-shaped steel doweled connections at ambient temperature presented.
Residual strength and failure modes of the assembly after 30-min partially exposure to the non-standard fire provided throughout the post-fire performance test.
Fire resistance of the assembly partially exposed to the non-standard fire highlighted.
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Milad Shabanian and Nicole Leo Braxtan
Thermomechanical behavior of intermediate-size beam-to-wall assemblies including Glulam-beams connected to cross-laminated timber (CLT) walls with T-shape steel doweled…
Abstract
Purpose
Thermomechanical behavior of intermediate-size beam-to-wall assemblies including Glulam-beams connected to cross-laminated timber (CLT) walls with T-shape steel doweled connections was investigated at ambient temperature (AT) and after and during non-standard fire exposure.
Design/methodology/approach
Three AT tests were conducted to evaluate the load-carrying capacity and failure modes of the assembly at room temperature. Two post-fire performance (PFP) tests were performed to study the impact of 30-min (PFP30) and 60-min (PFP60) partial exposure to a non-standard fire on the residual strength of the assemblies. The assemblies were exposed to fire in a custom-designed frame, then cooled and loaded to failure. A fire performance (FP) test was conducted to study the fire resistance (FR) during non-standard fire exposure by simultaneously applying fire and a mechanical load equal to 65% of the AT load carrying capacity.
Findings
At AT, embedment failure of the dowels followed by splitting failure at the Glulam-beam and tensile failure of the epoxy between the layers of CLT-walls were the dominant failure modes. In both PFP tests, the plastic bending of the dowels was the only observed failure mode. The residual strength of the assembly was reduced 14% after 30 min and 37% after 60 min of fire exposure. During the FP test, embedment failure of timber in contact with the dowels was the only major failure mode, with the maximum rate of displacement at 51 min into the fire exposure.
Originality/value
This is the first time that the thermomechanical performance of such an assembly with a full-contact connection is presented.
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Natalie Ishmael, Anura Fernando, Sonja Andrew and Lindsey Waterton Taylor
This paper aims to provide an overview of the current manufacturing methods for three-dimensional textile preforms while providing experimental data on the emerging techniques of…
Abstract
Purpose
This paper aims to provide an overview of the current manufacturing methods for three-dimensional textile preforms while providing experimental data on the emerging techniques of combining yarn interlocking with yarn interlooping.
Design/methodology/approach
The paper describes the key textile technologies used for composite manufacture: braiding, weaving and knitting. The various textile preforming methods are suited to different applications; their capabilities and end performance characteristics are analysed.
Findings
Such preforms are used in composites in a wide range of industries, from aerospace to medical and automotive to civil engineering. The paper highlights how the use of knitting technology for preform manufacture has gained wider acceptance due to its flexibility in design and shaping capabilities. The tensile properties of glass fibre knit structures containing inlay yarns interlocked between knitted loops are given, highlighting the importance of reinforcement yarns.
Originality/value
The future trends of reinforcement yarns in knitted structures for improved tensile properties are discussed, with initial experimental data.
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Xinghua Shan, Zhiqiang Zhang, Fei Ning, Shida Li and Linlin Dai
With the yearly increase of mileage and passenger volume in China's high-speed railway, the problems of traditional paper railway tickets have become increasingly prominent…
Abstract
Purpose
With the yearly increase of mileage and passenger volume in China's high-speed railway, the problems of traditional paper railway tickets have become increasingly prominent, including complexity of business handling process, low efficiency of ticket inspection and high cost of usage and management. This paper aims to make extensive references to successful experiences of electronic ticket applications both domestically and internationally. The research on key technologies and system implementation of railway electronic ticket with Chinese characteristics has been carried out.
Design/methodology/approach
Research in key technologies is conducted including synchronization technique in distributed heterogeneous database system, the grid-oriented passenger service record (PSR) data storage model, efficient access to massive PSR data under high concurrency condition, the linkage between face recognition service platforms and various terminals in large scenarios, and two-factor authentication of the e-ticket identification code based on the key and the user identity information. Focusing on the key technologies and architecture the of existing ticketing system, multiple service resources are expanded and developed such as electronic ticket clusters, PSR clusters, face recognition clusters and electronic ticket identification code clusters.
Findings
The proportion of paper ticket printed has dropped to 20%, saving more than 2 billion tickets annually since the launch of the application of E-ticketing nationwide. The average time for passengers to pass through the automatic ticket gates has decreased from 3 seconds to 1.3 seconds, significantly improving the efficiency of passenger transport organization. Meanwhile, problems of paper ticket counterfeiting, reselling and loss have been generally eliminated.
Originality/value
E-ticketing has laid a technical foundation for the further development of railway passenger transport services in the direction of digitalization and intelligence.
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Mahmud Hassan and Rumman Hassan
Waiting is associated with pain and stress that leads to frustration. However, consumer narratives may help cope with the stress associated with such waiting. This study aims to…
Abstract
Purpose
Waiting is associated with pain and stress that leads to frustration. However, consumer narratives may help cope with the stress associated with such waiting. This study aims to understand consumer waiting behaviours within online communities.
Design/methodology/approach
Data was gathered following a netnographic approach from a Facebook brand community (FBC) by downloading and archiving the threads related to members’ waiting behaviours. This resulted in 91 pages of data, with 438 individual comments and 179 distinct threads.
Findings
The data revealed that members of the sampled FBC exercised waiting behaviour. The authors confirm that waiting for a product is associated with both negative outcomes (frustration, boredom, etc.), but positive ones (create stronger ties with the brand and fellow members, etc.). Members of the FBC exhibited reduced consumer anxiety and stress during the waiting period.
Research limitations/implications
This study found 13 waiting behaviours within the FBC and supports the idea that new value-creating behaviours are noticed within the context of FBCs.
Originality/value
This study focuses on waiting within a goods-based context (waiting to be served has been examined predominantly within the service sector). The study explored the behaviours of consumers who use social media to complain about extended waiting periods to receive the product along with other consumer reactions to these waiting crowds to reduce the emotional pain associated with such delays.
Propósito
La espera se asocia con el dolor y el estrés, lo que lleva a la frustración. Sin embargo, el relato de otros consumidores puede ayudar a hacer frente al estrés asociado a dicha espera. Este trabajo busca entender el comportamiento de espera de los consumidores dentro de las comunidades online.
Diseño/metodología/enfoque
Los datos fueron recopilados siguiendo un enfoque netnográfico de una comunidad de marca en Facebook (CMF) mediante la descarga de mensajes; sólo los hilos relacionados con los comportamientos de espera de los miembros fueron descargados y archivados. Esto resultó en 91 páginas de datos con 438 comentarios individuales y 179 hilos distintos.
Hallazgos
Los datos revelan que en Facebook se dan comportamientos de espera. Confirmamos que la espera de un producto no sólo está asociada a resultados negativos (frustración, aburrimiento, etc.), sino también a resultados positivos (crear lazos más fuertes con la marca y los compañeros). Además, se comprueba que los miembros de la CMF reducen la ansiedad y el estrés del consumidor durante el período de espera.
Limitaciones/implicaciones de la investigación
Este trabajo encuentra 13 comportamientos de espera dentro de una CMF
Originalidad/valor
Este trabajo se centra en la espera dentro del contexto basado en los bienes (la espera para ser atendido ha sido examinada principalmente dentro del sector de servicios). Además, no sólo nos centramos en los consumidores que utilizan los medios sociales para quejarse de una espera más larga en la recepción del producto, sino también en la reacción de otros consumidores a estas esperas para reducir el dolor emocional asociado a dicho retraso.
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Jonas Tana, Emil Eirola and Kristina Eriksson-Backa
This paper brings focus and attention to the aspect of time within health information behaviour. The purpose of this paper is to critically assess and present strengths and…
Abstract
Purpose
This paper brings focus and attention to the aspect of time within health information behaviour. The purpose of this paper is to critically assess and present strengths and weaknesses of utilising the infodemiology approach and metrics as a novel way to examine temporal variations and patterns of online health information behaviour. The approach is shortly exemplified by presenting empirical evidence for temporal patterns of health information behaviour on different time-scales.
Design/methodology/approach
A short review of online health information behaviour is presented and methodological barriers to studying the temporal nature of this behaviour are emphasised. To exemplify how the infodemiology approach and metrics can be utilised to examine temporal patterns, and to test the hypothesis of existing rhythmicity of health information behaviour, a brief analysis of longitudinal data from a large discussion forum is analysed.
Findings
Clear evidence of robust temporal patterns and variations of online health information behaviour are shown. The paper highlights that focussing on time and the question of when people engage in health information behaviour can have significant consequences.
Practical implications
Studying temporal patterns and trends for health information behaviour can help in creating optimal interventions and health promotion campaigns at optimal times. This can be highly beneficial for positive health outcomes.
Originality/value
A new methodological approach to study online health information behaviour from a temporal perspective, a phenomenon that has previously been neglected, is presented. Providing evidence for rhythmicity can complement existing epidemiological data for a more holistic picture of health and diseases, and their behavioural aspects.
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